308 research outputs found
[Respuesta del P. Leonardo Lessio a algunas preguntas].
No full textEn el fol. 214v se dice: "Respuesta del P. Leonardo Lessio acerca de algunas preguntas (algunas objeciones que no se encuentran; su solución; alabanzas de la Concordia)".Incipit: "Reverende in Christo Pater. Pax Christi. Legi quae V.R. misit addenda Concordiae. Omnia meditata, solida, clara. Rogavi P.V. Provincialem ut mox Antuerpiae curet excudi..." (fol. 213).Explicit: "... post breviores commentarios apud ingeniosos proficiunt. His vale, R.P. Mei memor in sanctis sacrificiis, salutem precatur et longam valetudinem R.V. P. Rector vocatur Franciscus florentinus. Lovanii 13 martii 94. R.V. servus in Christo, Leonardus Lessius" (fol. 214)
Vettori dei giallumi della vite, fra vecchie conoscenze e nuove acquisizioni
No full textI giallumi della vite sono malattie associate a fitoplasmi segnalate per la prima volta in Italia all’inizio degli anni ’70 che si sono ampiamente diffuse, tanto da diventare un serio problema fitosanitario di rilevanza nazionale. Anche se molti agenti causali sono stati ritrovati in vite (Ca. Phytoplasma asteris, Ca. P. trifolii, Ca. P. fraxini) particolarmente dannosi sono il Ca. P. vitis agente della Flavescenza dorata (FD) nelle regioni centro settentrionali ed il Ca. P. solani agente del Legno nero (LN) con attacchi più localizzati ma diffusi in tutto il Paese. Recentemente in molte Regioni Italiane è stato osservato un aumento del numero di viti manifestanti sintomi ascrivibili ai giallumi. Le cause di questa recrudescenza possono essere molteplici ed ascrivibili ai cambiamenti dell’ambiente, degli ospiti vegetali, dei patogeni, degli insetti vettori o dei rapporti tra queste diverse componenti, nonché ad una minore efficacia degli insetticidi attualmente disponibili. Nel presente lavoro vengono trattate le attuali conoscenze sui vettori della FD e del LN per un loro efficace contenimento
Describing the spatio-temporal variability of vines and soil by satellite-based spectral indices: A case study in Apulia (South Italy).
No full textA time series of Landsat 8 OLI (L8 OLI) multispectral images acquired between May 2013 and February 2016 were used to investigate vigour, vine and soil water content in a vineyard of Moscato Reale (syn. Moscato Bianco) sited in the Castel del Monte DOCG area. Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) were calculated and compared with vine midday stem water potential (ΨMDstem) and soil volume water content (VWC), to calibrate estimation models. Estimation models were calibrated using already existing ground observation datasets from previous ordinary vineyard management operations: ΨMDstem was measured at two different locations in vineyard at 6 different dates in summer 2014; VWC was continuously measured from June to October 2014 and from January to September 2015. Results showed that: a) vine stem water potential can be locally estimated with an accuracy ranging from ±0.046 (high vigour vines) to ±0.127 (low vigour vines) MPa; b) soil volume water content can be locally estimated with an accuracy of about ±1.7%. Medium resolution satellite imagery proved, therefore, to be effective, at vineyard level, to describe vigour, vine and soil water status and their seasonality. This is an important issue to focus on since, as Landsat 8 images are free, the entire process is economic enough to be consistent with cost and incoming of the farming syste
A mathematical model of flavescence dorée epidemiology
No full textFlavescence dorée (FD) is a disease of grapevine transmitted by an insect vector, Scaphoideus titanus Ball.
At present, no prophylaxis exists, so mandatory control procedures (e.g. removal of infected plants, and
insecticidal sprays to avoid transmission) are in place in Italy and other European countries. We propose
a model of the epidemiology of FD by taking into account the different aspects involved into the transmis-
sion process (acquisition of the disease, latency and expression of symptoms, recovery rate, removal and
replacement of infected plants, insecticidal treatments, and the effect of hotbeds). The model was con-
structed as a system of first order nonlinear ODEs in four compartment variables. A bifurcation analysis
shows that, in the absence of hotbeds, the state of healthy vineyard is stable, if removal and replacement
of infected plants is implemented. In the presence of hotbeds, depending on the grapevine density, we
find either a single family of equilibria in which the health of the vineyard gradually deteriorates for pro-
gressively more severe hotbeds, or multiple equilibria that give rise to sudden transitions from a nearly
healthy vineyard to a highly deteriorated one when the severity of the hotbeds crosses a critical value.
These results show the long-term risks in planting new vineyards in environmental situations where
strong hotbeds of FD are present or may arise in the surroundings
A comparison between multispectral aerial and satellite imagery in precision viticulture
No full textIn this work we tested consistency and reliability of satellite-derived Prescription Maps (PMs) respect to those that can be obtained by aerial imagery. Test design considered a vineyard of Moscato Reale sited in Apulia (South-Eastern Italy) and two growing seasons (2013 and 2014). Comparisons concerned Landsat 8 OLI images and aerial datasets from airborne RedLake MS4100 multispectral camera. We firstly investigated the role of spatial resolution in radiometric features of data and, in particular, of NDVI maps and consequently of vigour maps. We first measured the maximum expected correlation between satellite- and aerial-derived maps. We found that, without any pixel selection and spatial interpolation, correlation ranges between 0.35 and 0.60 depending on the degree of heterogeneity of the vineyard. We also found that this result can be improved by operating a selection of those pixels representing vines canopy in aerial imagery and spatially interpolating them. In this way correlation coefficient can be improved up to 0.85 (minimum 0.60) suggesting an excellent capability of satellite data to approximate aerial ones at vineyard level. Prescription maps derived from vigour one demonstrated to be spatially consistent; but we also found that the quantitative interpretation of mapped vigour was changing in strength according to datasets and time of acquisition. Therefore, in spite of a satisfying consistency of spatial distribution, results showed that vigour strength at vineyard level from aerial and satellite datasets is generally not consistent, partially for the presence of a bias (that we modelled)
Cluster Models for Studying CO<inf>2</inf> Reduction on Semiconductor Photoelectrodes
No full textSunlight-powered CO2-photoelectroreduction is a promising and potentially sustainable route to recycle CO2 byproducts back into energy-dense liquid fuels. One of the most intriguing processes known to date is the pyridinium-catalyzed CO2 reduction on p-type GaP photoelectrodes, where conversion to methanol has reported faradaic efficiencies nearing 100 %. Modeling this reactive environment requires understanding energetics of differently charged species at semiconductor electrodes, so we develop a cluster model and benchmark binding energies from it to those from Kohn–Sham density functional theory calculations that employ periodic boundary conditions. We then use this cluster model to theoretically predict structures and binding energies for charged and neutral adsorbates on the GaP(110) surface with and without the presence of van der Waals interactions and implicit solvation. We discuss the relative magnitudes of binding energy contributions for different adsorbates considered relevant in this CO2 reduction process and provide details showing pitfalls when using cluster models
(Very) Fast astronomical photometry for meter-class telescopes
No full textOur team at the INAF-Astronomical Observatory of Padova and the University of Padova is engaged in the design, construction and operations of instruments with very high time accuracy in the optical band for applications to High Time Resolution Astrophysics and Quantum Astronomy. Two instruments were built to perform photon counting with sub-nanosecond temporal accuracy, Aqueye+ and Iqueye. Aqueye+ is regularly mounted at the 1.8m Copernicus telescope in Asiago, while Iqueye was mounted at several 4m class telescopes around the world and is now attached through the Iqueye Fiber Interface to the 1.2m Galileo telescope in Asiago. They are used to perform coordinated high time resolution optical observations and, for the first time ever, experiments of optical intensity interferometry on a baseline of a few kilometers. We report on recent technological developments and scientific results obtained within the framework of this project...
- …
